Can I share the first christmas I spent alone, after all my kids had left home? It might help.
Several of my friends invited me to join them but all I could think of was that it would - for the first time in many, many years, be a time I could please myself.
To alleviate any pain a direct refusal would cause, I told each I was spending it with the other one (which meant they wouldn't call me, either).
On Christmas Day I got up early - habit of a lifetime - had several cups of tea, fed the dogs and then wrapped up warm and took them for a long, slow walk on Hampstead Heath.
I don't think I saw more than 2 other people - also walking dogs - and it was wonderful.
We got back home, I made a hot drink, put the fire on (open coal fire) and cuddled up with the dogs until we'd all thawed out.
One of my requests that year was for a complete set of (what was then the only) Star Wars films (three). My Christmas dinner was egg and chips with brown bread and butter and then I curled up with the dogs and watched all three films, one after the other!
It was WONDERFUL!!!
I went to bed happy, relaxed and ready for whatever was coming next.
Please don't think of Christmas Day alone, but of Christmas Day on your own - a vastly different kettle of fish.